<?php
defined('BASE') or exit('Access Denied!');

/**
 * Obullo Framework (c) 2009.
 *
 * PHP5 MVC Based Minimalist Software.
 * 
 * @package         obullo       
 * @author          obullo.com
 * @copyright       Ersin Güvenç (c) 2009.
 * @filesource
 * @license
 */
 
Class TrackbackException extends CommonException {}  
 
// ------------------------------------------------------------------------

/**
 * Trackback Class
 *
 * Trackback Sending/Receiving Class
 * 
 * @package       Obullo
 * @subpackage    Libraries
 * @category      Libraries
 * @author        Ersin Güvenç
 * @link          
 */
class OB_Trackback {
        
    public $time_format    = 'local';
    public $charset        = 'UTF-8';
    public $data           = array('url' => '', 'title' => '', 'excerpt' => '', 'blog_name' => '', 'charset' => '');
    public $convert_ascii  = TRUE;
    public $response       = '';
    public $error_msg      = array();

    /**
     * Constructor
     *
     * @access    public
     */
    public function __construct()
    {
        log_message('debug', "Trackback Class Initialized");
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Send Trackback
     *
     * @access    public
     * @param    array
     * @return    bool
     */    
    public function send($tb_data)
    {        
        if ( ! is_array($tb_data))
        {
            $this->set_error('The send() method must be passed an array');
            return FALSE;
        }
        
        // Pre-process the Trackback Data
        foreach (array('url', 'title', 'excerpt', 'blog_name', 'ping_url') as $item)
        {
            if ( ! isset($tb_data[$item]))
            {
                $this->set_error('Required item missing: '.$item);
                return FALSE;
            }
            
            switch ($item)
            {
                case 'ping_url'    : $$item = $this->extract_urls($tb_data[$item]);
                    break;
                case 'excerpt'     : $$item = $this->limit_characters($this->convert_xml(strip_tags(stripslashes($tb_data[$item]))));
                    break;
                case 'url'         : $$item = str_replace('&#45;', '-', $this->convert_xml(strip_tags(stripslashes($tb_data[$item]))));
                    break;
                default            : $$item = $this->convert_xml(strip_tags(stripslashes($tb_data[$item])));
                    break;
            }

            // Convert High ASCII Characters
            if ($this->convert_ascii == TRUE)
            {
                if ($item == 'excerpt')
                {
                    $$item = $this->convert_ascii($$item);
                }
                elseif ($item == 'title')
                {
                    $$item = $this->convert_ascii($$item);
                }
                elseif($item == 'blog_name')
                {
                    $$item = $this->convert_ascii($$item);
                }
            }
        }

        // Build the Trackback data string
        $charset = ( ! isset($tb_data['charset'])) ? $this->charset : $tb_data['charset'];
        
        $data = "url=".rawurlencode($url)."&title=".rawurlencode($title)."&blog_name=".rawurlencode($blog_name)."&excerpt=".rawurlencode($excerpt)."&charset=".rawurlencode($charset);
                
        // Send Trackback(s)
        $return = TRUE;
        if (count($ping_url) > 0)
        {
            foreach ($ping_url as $url)
            {
                if ($this->process($url, $data) == FALSE)
                {
                    $return = FALSE;
                }
            }    
        }

        return $return;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Receive Trackback  Data
     *
     * This function simply validates the incoming TB data.
     * It returns false on failure and true on success.
     * If the data is valid it is set to the $this->data array
     * so that it can be inserted into a database.
     *
     * @access    public
     * @return    bool
     */    
    public function receive()
    {                      
        foreach (array('url', 'title', 'blog_name', 'excerpt') as $val)
        {
            if ( ! isset($_POST[$val]) OR $_POST[$val] == '')
            {
                $this->set_error('The following required POST variable is missing: '.$val);
                return FALSE;
            }
            
            $this->data['charset'] = ( ! isset($_POST['charset'])) ? 'auto' : strtoupper(trim($_POST['charset']));
    
            if ($val != 'url' && function_exists('mb_convert_encoding'))
            {
                $_POST[$val] = mb_convert_encoding($_POST[$val], $this->charset, $this->data['charset']);
            }
            
            $_POST[$val] = ($val != 'url') ? $this->convert_xml(strip_tags($_POST[$val])) : strip_tags($_POST[$val]);
            
            if ($val == 'excerpt')
            {
                $_POST['excerpt'] = $this->limit_characters($_POST['excerpt']);
            }
            
            $this->data[$val] = $_POST[$val];
        }

        return TRUE;
    }    
    
    // --------------------------------------------------------------------
    
    /**
     * Send Trackback Error Message
     *
     * Allows custom errors to be set.  By default it
     * sends the "incomplete information" error, as that's
     * the most common one.
     *
     * @access   public
     * @param    string
     * @return   void
     */    
    public function send_error($message = 'Incomplete Information')
    {
        echo "<?xml version=\"1.0\" encoding=\"utf-8\"?".">\n<response>\n<error>1</error>\n<message>".$message."</message>\n</response>";
        exit;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Send Trackback Success Message
     *
     * This should be called when a trackback has been
     * successfully received and inserted.
     *
     * @access    public
     * @return    void
     */        
    public function send_success()
    {
        echo "<?xml version=\"1.0\" encoding=\"utf-8\"?".">\n<response>\n<error>0</error>\n</response>";
        exit;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Fetch a particular item
     *
     * @access    public
     * @param    string
     * @return    string
     */    
    public function data($item)
    {
        return ( ! isset($this->data[$item])) ? '' : $this->data[$item];
    }

    // --------------------------------------------------------------------
    
    /**
     * Process Trackback
     *
     * Opens a socket connection and passes the data to
     * the server.  Returns true on success, false on failure
     *
     * @access   public
     * @param    string
     * @param    string
     * @return   bool
     */    
    public function process($url, $data)
    {
        $target = parse_url($url);
    
        // Open the socket
        if ( ! $fp = @fsockopen($target['host'], 80))
        {
            $this->set_error('Invalid Connection: '.$url);
            return FALSE;
        }

        // Build the path
        $ppath = ( ! isset($target['path'])) ? $url : $target['path'];
        
        $path = (isset($target['query']) && $target['query'] != "") ? $ppath.'?'.$target['query'] : $ppath;

        // Add the Trackback ID to the data string
        if ($id = $this->get_id($url))
        {
            $data = "tb_id=".$id."&".$data;
        }

        // Transfer the data
        fputs ($fp, "POST " . $path . " HTTP/1.0\r\n" );
        fputs ($fp, "Host: " . $target['host'] . "\r\n" );
        fputs ($fp, "Content-type: application/x-www-form-urlencoded\r\n" );
        fputs ($fp, "Content-length: " . strlen($data) . "\r\n" );
        fputs ($fp, "Connection: close\r\n\r\n" );
        fputs ($fp, $data);

        // Was it successful?
        $this->response = "";
        
        while( ! feof($fp))
        {
            $this->response .= fgets($fp, 128);
        }
        @fclose($fp);
        
        if (stristr($this->response, '<error>0</error>') === FALSE)
        {
            $message = 'An unknown error was encountered';
            
            if (preg_match("/<message>(.*?)<\/message>/is", $this->response, $match))
            {
                $message = trim($match['1']);
            }
            
            $this->set_error($message);
            return FALSE;
        }

        return TRUE;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Extract Trackback URLs
     *
     * This function lets multiple trackbacks be sent.
     * It takes a string of URLs (separated by comma or
     * space) and puts each URL into an array
     *
     * @access   public
     * @param    string
     * @return   string
     */    
    public function extract_urls($urls)
    {        
        // Remove the pesky white space and replace with a comma.
        $urls = preg_replace("/\s*(\S+)\s*/", "\\1,", $urls);
        
        // If they use commas get rid of the doubles.
        $urls = str_replace(",,", ",", $urls);
        
        // Remove any comma that might be at the end
        if (substr($urls, -1) == ",")
        {
            $urls = substr($urls, 0, -1);
        }
                
        // Break into an array via commas
        $urls = preg_split('/[,]/', $urls);
        
        // Removes duplicates
        $urls = array_unique($urls);
        
        array_walk($urls, array($this, 'validate_url'));
        
        return $urls;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Validate URL
     *
     * Simply adds "http://" if missing
     *
     * @access   public
     * @param    string
     * @return   string
     */    
    public function validate_url($url)
    {
        $url = trim($url);

        if (substr($url, 0, 4) != "http")
        {
            $url = "http://".$url;
        }
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Find the Trackback URL's ID
     *
     * @access   public
     * @param    string
     * @return   string
     */    
    public function get_id($url)
    {    
        $tb_id = "";
        
        if (strstr($url, '?'))
        {
            $tb_array = explode('/', $url);
            $tb_end   = $tb_array[count($tb_array)-1];
            
            if ( ! is_numeric($tb_end))
            {
                $tb_end  = $tb_array[count($tb_array)-2];
            }
            
            $tb_array = explode('=', $tb_end);
            $tb_id    = $tb_array[count($tb_array)-1];
        }
        else
        {
            $url = rtrim($url, '/');
                
            $tb_array = explode('/', $url);
            $tb_id    = $tb_array[count($tb_array)-1];
            
            if ( ! is_numeric($tb_id))
            {
                $tb_id  = $tb_array[count($tb_array)-2];
            }
        }    
                
        if ( ! preg_match ("/^([0-9]+)$/", $tb_id))
        {
            return false;
        }
        else
        {
            return $tb_id;
        }        
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Convert Reserved XML characters to Entities
     *
     * @access   public
     * @param    string
     * @return   string
     */
    public function convert_xml($str)
    {
        $temp = '__TEMP_AMPERSANDS__';
        
        $str = preg_replace("/&#(\d+);/", "$temp\\1;", $str);
        $str = preg_replace("/&(\w+);/",  "$temp\\1;", $str);
        
        $str = str_replace(array("&","<",">","\"", "'", "-"),
                           array("&amp;", "&lt;", "&gt;", "&quot;", "&#39;", "&#45;"),
                           $str);
            
        $str = preg_replace("/$temp(\d+);/","&#\\1;",$str);
        $str = preg_replace("/$temp(\w+);/","&\\1;", $str);
            
        return $str;
    }    
    
    // --------------------------------------------------------------------
    
    /**
     * Character limiter
     *
     * Limits the string based on the character count. Will preserve complete words.
     *
     * @access   public
     * @param    string
     * @param    integer
     * @param    string
     * @return   string
     */
    public function limit_characters($str, $n = 500, $end_char = '&#8230;')
    {
        if (strlen($str) < $n)
        {
            return $str;
        }

        $str = preg_replace("/\s+/", ' ', str_replace(array("\r\n", "\r", "\n"), ' ', $str));
    
        if (strlen($str) <= $n)
        {
            return $str;
        }
                                        
        $out = "";
        foreach (explode(' ', trim($str)) as $val)
        {
            $out .= $val.' ';            
            if (strlen($out) >= $n)
            {
                return trim($out).$end_char;
            }        
        }
    }
    
    // --------------------------------------------------------------------
    
    /**
     * High ASCII to Entities
     *
     * Converts Hight ascii text and MS Word special chars
     * to character entities
     *
     * @access   public
     * @param    string
     * @return   string
     */
    public function convert_ascii($str)
    {
       $count    = 1;
       $out    = '';
       $temp    = array();
        
       for ($i = 0, $s = strlen($str); $i < $s; $i++)
       {
           $ordinal = ord($str[$i]);
        
           if ($ordinal < 128)
           {
               $out .= $str[$i];            
           }
           else
           {
               if (count($temp) == 0)
               {
                   $count = ($ordinal < 224) ? 2 : 3;
               }
            
               $temp[] = $ordinal;
            
               if (count($temp) == $count)
               {
                   $number = ($count == 3) ? (($temp['0'] % 16) * 4096) + (($temp['1'] % 64) * 64) + ($temp['2'] % 64) : (($temp['0'] % 32) * 64) + ($temp['1'] % 64);
    
                   $out .= '&#'.$number.';';
                   $count = 1;
                   $temp = array();
               }
           }
       }
    
       return $out;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Set error message
     *
     * @access   public
     * @param    string
     * @return   void
     */    
    public function set_error($msg)
    {
        log_message('error', $msg);
        
        $this->error_msg[] = $msg;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Show error messages
     *
     * @access   public
     * @param    string
     * @param    string
     * @return   string
     */    
    public function display_errors($open = '<p>', $close = '</p>')
    {    
        $str = '';
        foreach ($this->error_msg as $val)
        {
            $str .= $open.$val.$close;
        }
    
        return $str;
    }

}
// END Trackback Class

/* End of file Trackback.php */
/* Location: ./base/libraries/Trackback.php */